Efficient capture of radioactive iodine by a new bismuth-decorated electrospinning carbon nanofiber

Abstract Radioactive iodine isotopes that are discharged into environment have been of significant concern due to its long-term impact on public health. In this work, a new bismuth-based composite named Bi@ESCNF (bismuth-decorated electrospinning carbon nanofibers) was prepared and investigated for capturing iodine-129 (129I). This material used an electrospinning carbon nanofiber membrane as the substrate and metallic Bi nanoparticles were uniformly inlaid on the fibers, providing a rich active site to capture iodine gas. Due to the strong affinity of bismuth and iodine, Bi@ESCNF exhibited a very high iodine uptake capacity up to 559 mg/g after exposure to iodine for 4 h at 200 °C which could reach approximately two-fold higher than that of the commercial silver exchanged zeolite and even larger than other reported bismuth-based adsorbents. The uptake mechanism was also unraveled by the combined BET, PXRD, SEM, TEM, XPS, and Raman spectra characterizations. It is found that such excellent iodine capture property by this material was attributed to the chemical reaction between bismuth and iodine, which will generate a stable phase of BiI3, and possess a huge specific surface area of 537 m2/g. Thus, our results showed that the new and highly efficient Bi@ESCNF would be a promising adsorbent for radioactive iodine removal.